Currently, a system is available that sends data detected by a sensor, e.g. a temperature sensor, to a central apparatus such as a host computer, for example, and that executes a variety of applications including controlling air conditioning in response to the data received by the central apparatus.
In such a system, the sensor sends to the central apparatus the detected data and a sensor ID uniquely identifying the sensor. The central apparatus accesses a database having stored the sensor ID and attribute information indicating an attribute of the sensor and mapped to the sensor, and acquires the attribute information corresponding to the sensor ID. The central apparatus includes a cache memory, and stores temporarily the acquired attribute information in the cache memory. If data is acquired from the same sensor in a subsequent cycle, the central apparatus acquires the attribute information from the cache memory rather than from the database. The access load to the database is thus reduced.
The sensors include not only a continuous connection type that usually remains connected to a network and sends detected data on a real-time basis, but also an intermittent connection type that sends data intermittently, and a hybrid type that is switched appropriately between a continued connection operation and an intermittent connection operation.
The intermittent connection type sensor detects data periodically, and stores the detected data in a memory therein. When connected to the network, the intermittent connection type sensor sends the data stored in the memory to the central apparatus in a data burst.